Abstract
This paper proposes a stereolithography method in which photopolymer resin is exposed to ultraviolet ray through grayscale mask to control light intensity pattern. Since 2-D density pattern of the grayscale gradation is transferred to the curing thickness pattern, the fabricated object can have smoothly curved or patterned surface without steps which inevitably appear in case of conventional layer-by-layer stereolithography. A ultraviolet light source, photopolymer resin and mask material for grayscale mask stereolithography are discussed, and post-curing in the water for less distortion is proposed. One of the possible applications of the grayscale mask stereolithography is fabrication of optical lenses. This paper shows fabrication examples of prism lens and spherical lens array using grayscale pattern calculated from the target surface pattern, and quasi-relief using usual photograph film as a mask.
